Method of making cartridges



I July 27, 4 M. L. A. PAULVE f 5 METHOD OF MAKING CARTRIDGES Filed Sept. 30, 1949 2 Shets-Sheet 1 y 27, Q LI -PAULVE 2,684,502

METHOD MAKING CARTRIDGES Filed Sept. 50, 1949 I 2 Sheets-Sheet 2 "Q B Q 9 a L: bi

Q Q "U I i Patented July 27, 1954 UNITED STATES PATENT QFFHCE 3 Claims.

This invention relates to an improved construction of cartridges, especially sporting cartridges.

While metal is frequently used in the manufacture of sporting cartridge cases, this oilers some drawbacks. Where thin-gauge metal is used to form such a cartridge-case, special sizes of wadding are required to plug the cartridge, and this constitutes a difficulty in loading the cartridge for the gunsmith. Where on the other hand the metal of the cartridge case is heavy, it will tend to acquire a permanent set after the shot is fired so that ejection of the used cartridge case is made diilicult.

It is an object of this invention to eliminate the above limitations in the manufacture of sporting cartridges.

Another object is to provide an improved form of cartridge in which the main body of the cartridge case is formed of a plastic material, while retaining the advantages of metal cartridge cases as to strength, deformability, and dimensional stability.

A further object is to provide an improved sporting cartridge having improved ballistic characteristics and in which the main body of the case may be accuratel and economically produced by such methods as injection-molding aplastic.

A more specific object is to provide an improved cartridge case which comprises a main body of plastic material over at least part of the outer periphery of which there extends a thin strong shell, casing or liner as of metal.

A further object is to provide such a cartridge in which the internal and external contours may be formed with high accuracy to conform with the bore and chamber of a given sporting gun.

Further objects include the provision of an improved method of, and equipment for, producing cartrdige cases of the above-described charactor.

The improved method of producing a cartridge case according to my invention may comprise first forming an outer shell, casing or liner of a strong deformable material, preferably metal, designed so as to extend over the full length, or only part of the length, of the cartridge-case, then injection-molding in the shell thus provided a main body of plastic material. Where only a partial metal shell i provided, said shell preferably comprises a base section encasing the base of the cartridge and a top or crimping section around the mouth of the cartridge case.

My invention further provides a. method of forming a cartridge case which comprises forming an external metallic shell designed to extend over at least part of the outer periphery of a cartridge case, forming an aperture in the base wall of said shell corresponding in location with that of the primer, inserting a, suitably contoured core into said shell in spaced relation with the walls thereof and moulding, preferably injectionmoulding, plastic material through said hole into the space between the shell and the core.

My invention also provides equipment for producing cartridge cases by the method described, and comprising a die having an inner contour accurately conforming to the outer contour of the finished cartridge case, a core within and spaced from said die conforming in its Outer contour with the inner contour of said cartridgecase, and an end-plate for sealing said die having an injection nozzle projecting therethrough into said die, preferably formed with radial discharge nozzles and having an extension adapted to project into an end hole of said core to centre the core both with respect to said die and said nozzle.

In the accompanying exemplary drawings:

Fig. 1 illustrates in cross-section full length casing for my improved cartridge.

Fig. 2 illustrates the same casing or lining with an aperture formed in its base wall to afford passage for the primer,

Fig. 3 illustrates by way of example one form of moulding or injection device.

Figs. l and 5 illustrate finished cartridge-cases.

Figs. 6 and 7 respectively show partial casing elements for the crimping end and the base of the cartridge.

Figs. 8, 9 and 19 show similar casing sections aft-er formation of apertures therein for a purpose to be described.

Fig. 11 shows one form of a pressure-moulding or die-casting equipment for such partial or sectional casings.

Figs. 12 and 13 represent finished cartridgecases with partial casing or lining elements.

In the embodiment of the invention illustrated in Figs. 1 to 5, a liner, shell, casing or sheath is first prepared by any suitable means. Said liner may be made of metal, and produced by extrusion from a disc-shaped blank. It may also be made of suitable plastic material and pressure-moulded or die-cast. The liner or sheath 1 may also be obtained in any other suitable way.

In the bottom or end wall of the liner I an aperture 3 is formed (Fig. 2) to correspond with the location of the primer.

The means shown in Fig. 3 comprise a die 4 sealed at its bottom end with a plate 5 in which may be inserted for instance an injection nozzle 6 projecting through the aperture 3 in the liner and formed with a main axial delivery duct 7 discharging into radial discharge ducts 8.

A core 9 of suitable shape is placed in the die 4 and is centred therein by means of an axial bore in into which a projecting end of the nozzle 6 extends. The external surface of the core is conformed to the shape of the internal surface of th finished. cartridge-case. Thus, for example, a shoulder H, and a tapered section a-b may be provided. The core 9 is smaller in efiective length than the liner I, so that the top end be of the liner extends beyond the top of the body 12 of plastic material (Figs. 4 and Plastic material I2 is delivered under pressure through the nozzle 6. The pressure of delivery applies the liner 1 against the die a and insures that an accurately appropriate external contour is provided for the finished cartridge-case.

Figs. 6 to 13 relate to an embodiment of the invention in which a cartridge-case is provided with partial or fragmentary liner sections rather than a solid unbroken liner over the full length of the cartridge-case as in the foregoing embodiment. The liner then comprises an upper liner ection or so-called crimping liner section 2' and a bottom or base liner section I.

To improve adhesion of the crimping liner section with the underlying plastic body l2, apertures [3 are provided into which said plastic material penetrates. Rather than apertures l3, suitable inwardly directed projections (not shown) could be provided in the top section I to achieve a similar purpose. In all other respects the arrangements are the same as described above in connection with Figs. 1 to 5, and will require no further description.

As shown in Fig. 13 an internal annular bead l4 may be integrally formed in the plastic body in the pressure moulding operation to provide means for stopping the plug or wadding.

It will of course be understood that various alterations may be made in the specific examples illustrated without exceedin the scope of the invention as defined in the ensuing claims.

What I claim is:

1. Method of manufacturing a cartridge case or the like, comprising the steps of forming an outer plain tubular and substantially cylindrical shell of a strong deformable material to extend over at least part of the outer periphery of a cartridge-case, forming a hole centrally of the base of said shell to correspond with the locaticn of a primer for said cartridge, inserting said shell into a moulding die, inserting a core within and spaced from said shell in said die, inserting axially in said core and through said hole an injection pipe with radial holes registering with the annular space between the core and the shell, and injecting a plastic through said pipe and holes, into the said space between said shell and said core, said injection being executed under a certain pressure which radially deforms the shell in order to form the desired shape of the bottom of the cartridge.

2. A method for producing an improved cartridge case which comprises forming a tubular top shell element and a plain tubular and cylindrical base shell element from a strong deformable material to extend over the top and base sections respectively of said cartridgecase, forming a hole centrally of the bottom of said base element, positioning said shell elements in a die and positioning a core axially of and spaced from said elements in said die, inserting axially in said core and through said hole an injection pipe with a series of radial holes registering with the annular space between the core and the shell elements, and injection-moulding a plastic through said pipe and bottom hole into the spacing between said elements and said core to form a body for said cartridge-case, said injection being executed under a certain pressure which radially deforms the base shell element in order to give it the desired shape.

3. An assembly for making a cartridge case of the type having at least one shell element of strong deformable material and an inner coating of plastic material, said assembly comprising a hollow molding die having a molding cavity of a contour conforming to the external contour of the case to be made and having opposin open ends, a core externally conforming to the internal contour of the case to be made removably positioned within the molding cavity inside the die and having a first end spaced inwardly from one of the open ends of the die and having a second end diametrically larger than the first end and engagin the inner wall of the die to close off the cavity at the other open end of the die, the portion of the core from the first end up to a point spaced axially from the second end being radially spaced from the inner wall of the die, said core having a central, axial hole, an end plate for said, molding cavity transversely positioned on the open end of the die and enclosing said end to define an end wall of the molding cavity, said end plate having a central opening aligned with the hole in the core, a removable injection nozzle positioned through the opening in the end plate and having a closed end projecting into the hole in the core to retain the core in its centered position in the moldin cavity, said, nozzle having radial discharge openings formed inwardly of its closed end and registering with the space between the end of the core and the end plate.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 115,548 Wells May 30, 1871 237,700 Rodney Feb. 15, 1881 313,187 Dickerman Mar. 3, 1885 1,836,752 Goodwin Dec. 15, 1931 1,845,971 Katz Feb. 16, 1932 2,200,042 Salz May 7, 1940 2,408,629 Green Oct. 1, 1946 

